1. Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the same.
2. Related Art
A FIN-FET (Fin-type Field-Effect Transistor) is developed to improve a current driving ability of a transistor. When a polysilicon electrode is used for the FIN-FET, since it is difficult to adjust a threshold voltage, a FIN-FET using a metal gate electrode is taken into consideration. Full silicidation is available as one of metal gate electrode forming methods. When a gate electrode material composed of polysilicon is deposited, a step is formed on a surface of a gate electrode material by a body portion of the Fin. When the step is formed on the surface of the gate electrode material, a depth of focus has no margin when a gate electrode is patterned, which makes it impossible to minutely pattern the gate electrode. Accordingly, the gate electrode is patterned after the upper portion of the gate electrode material is flattened by CMP.
However, when the upper portion of the gate electrode material is flattened, the thickness of the gate electrode material on the Fin is made thinner than that of the gate electrode material disposed at sides of the Fin. When the gate electrode material is subjected to silicidation in this constitution, a relatively large amount of metal is supplied to the gate electrode material on the Fin. Accordingly, silicide containing a large amount of metal is formed on the Fin, and silicide containing a small amount of metal is formed in the sides of the Fin. Thus, when unreacted metal is removed, the silicide on the Fin is etched. As a result, a metal gate electrode is disconnected (has an increased resistance) on the Fin, from which a problem arises in that the Fin transistor does not operate normally.